This invention relates to a power generator circuit which is connectable to an alternator to produce a relatively high voltage DC output.
Various power generator circuits are known which are used in conjunction with motor vehicle alternators to provide a 120 volt or 240 volt DC output which can be used, for example, for operating power tools. It is also known to provide a welding output which is connected directly to the output of a bridge rectifier associated with the alternator. In the past, attempts have been made to feed the AC output of the alternator into a three phase step-up transformer in order to obtain a high voltage output. However, such circuits proved to have poor performance, with low power output and poor regulation.
A number of circuits employing capacitive voltage multipliers also exist. The main disadvantage of such circuits is that they require the capacitors to pass high ripple currents, which cause rapid heating of the capacitors. The operating temperature of the capacitors must generally be limited to 80.degree. C., which thus restricts the continuous output rating of such circuits. Apart from this, the electrolytic capacitors used are very expensive and deteriorate relatively rapidly in use, particularly when exposed to high temperatures.